1. Field of the Invention
The present invention relates to nanostructures, and more particularly, to coated nanoparticles and their use in detection systems and/or fluorescence compositions wherein the nanoparticles are surface coated with a polymeric or oxide material having fluorophores, luminophores or chemiluminescent species contacting the surface coating.
2. Background of the Related Art
The use of fluorescent nanoparticles as indicators in biological applications such as imaging and sensing has dramatically increased since the 1990s.[14] Metal-Enhanced Fluorescence (MEF) is a powerful technology [1], where the interactions of fluorophores with metallic nanoparticles results in fluorescence enhancement, increased photostability, decreased lifetimes due to increased rates of system radiative decay, [2] reduced blinking in single molecule fluorescence spectroscopy [1], and increased transfer distances for fluorescence resonance energy transfer 93]. However, almost all of the MEF applications to date have been performed on 2-dimensional surfaces, where glass microscope slides [4-6] or plastics [7-8], are used as the primary substrates that feature the silver nanostructures deposited using either wet-chemistry [4-8], electrochemically [9] or lithographically.
Single-molecule fluorescence spectroscopy is the prime tool in single nanoparticle sensing, and it provides several advantages over ensemble measurements, such as, the elimination of averaging of the spectral properties over all members of the ensemble, which can reveal fundamental features otherwise masked in ensemble experiments.[15] Accordingly, the use of fluorescent core-shell nanocomposites with single-molecule fluorescence spectroscopy is likely to enhance the capability of single nanoparticle sensing.